The examination of ceramics by x-ray powder diffraction

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Publication Type:

Journal Article

Authors:

Bimson, M.;

Source:

Studies in conservation, Volume 14, Number 2, p.83-89 (1969)

Keywords:

ceramics, diffraction, mullite, x-ray analysis, x-ray diffraction

Abstract:

By using x-ray powder diffraction to identify the crystalline constituents of ceramics, especially porcelains, a considerable amount of information can be obtained from a very small sample. The characteristic mineral in hard-paste porcelains, stonewares and high-fired earthenwares is shown to be mullite, an aluminium silicate, 3A12O3 · 2SiO2, (A.S.T.M. 15-776); where there is a high calcium content aluminium silicates may occur e.g. anorthite, CaO · Al2O3 · 2SiO2, (A.S.T.M. 10-379) and gehlenite 2CaO · Al2O3 · SiO2, (A.S.T.M. 9-216). Among the soft-paste porcelains, whitlockite, ß calcium orthophosphate, Ca3(PO4)2, (A.S.T.M. 9-169), is typical of those containing bone-ash, and enstatite, magnesium meta silicate, MgO · SiO2 (A.S.T.M. 7-216) is typical of those containing soapstone. The glassy-frit porcelains generally contain a calcium silicate, wollastonite or pseudowollastonite, CaO · SiO2, (A.S.T.M. 10-487 and 10-486). In addition, silica–either as a quartz or cristobalite–may occur in varying proportions in all these bodies.